Method for recycling furniture materials, in particular mattress, bed base, and seat materials, sheet of material obtained by such a method and related recycling facility

ABSTRACT

The invention relates to a method for recycling furniture materials, in particular mattress, bed base, and seat materials, the method comprising the following steps:
         a breakup step, in which base materials are obtained by breaking up the bedding element;   a sorting step ( 18 ), in which the base materials are separated into a plurality of families of materials according to the nature of the base materials;   a step ( 20 ) for grinding the different families of materials;   a mixing step ( 22 ), in which a mixture is prepared, the mixture comprising a predetermined amount of at least one family of ground materials;   a step ( 24 ) for forming a sheet of non-woven unconsolidated material from the mixture;   a step ( 27 ) for consolidating the non-woven unconsolidated sheet of material;   a step for calendering the non-woven consolidated sheet of material.

The present invention generally relates to the field of furniture and in particular that of bedding and seats for domestic furniture. More specifically, the invention according to a first aspect relates to a method for recycling bedding elements, notably mattresses or bed bases, and for recycling elements of seats, notably seat and seat-back cushions.

At their end of life, mattresses, bed bases and seats are today disposed of in landfills, or incinerated. These solutions are not satisfactory from the ecological point of view. Mattresses, bed bases and seats at the end of their life represent every year a significant stream. They consist of materials very different from each other, such as steel, wood, textiles, polyurethane foams, latex, etc. Incineration of these materials causes gas emissions, some of which may be toxic. When they are disposed of in landfills, the mattresses, bed bases and seats occupy a significant volume and are poorly adapted to the processing chains presently in place. Further, certain materials in the long run do not transform into an organic material.

In this context, the invention aims at proposing a method for recycling furniture products, which is more satisfactory from an ecological point of view than disposal in a landfill or incineration.

For this purpose, the invention deals with a method for recycling furniture products, notably mattresses, bed bases and seats, the method comprising the following steps:

-   -   a breakup step, in which base materials are obtained by breaking         up the furniture product;     -   a sorting step, in which the base materials are separated into a         plurality of families of materials, depending on the nature of         the base materials;     -   a step for grinding the different families of materials;     -   a mixing step, in which a mixture is prepared, the mixture         comprising a predetermined amount of at least one family of         ground materials;     -   a step for forming a sheet of non-woven unconsolidated material         from the mixture;     -   a step for consolidating the non-woven unconsolidated material         sheet;     -   a step for calendering the non-woven consolidated material         sheet.

The method may further have one or several of the features below, considered individually and according to all the technically possible combinations:

-   -   in the sorting step, the base materials are sorted out so as to         separate at least first and third families of materials, the         first family of materials grouping base materials which both do         not contain any textile fibers but in majority contain         polyurethane, and the third family of materials grouping the         base materials containing textile fibers,     -   in the sorting step, the base materials are sorted out so as to         separate at least one second family of materials, grouping the         base materials in majority containing latex,     -   the method comprises a step for disinfecting the elements to be         treated, before the breakup step,     -   disinfection of the elements to be treated is carried out via a         chemical route by spraying a disinfecting product on an external         surface of the bedding elements, or by exposing bedding elements         to microwave radiation,     -   in the step for forming the non-woven unconsolidated material         sheet, the mixture is carried away and dispersed by an air flow         in a chamber, according to the method known as an air lay         method,     -   in the consolidation step, the non-woven unconsolidated material         sheet is thermally consolidated,     -   a mixture comprises by weight between 40% and 80% of the first         family of materials, between 15% and 45% of the third family of         materials, and between 5% and 20% of a mixture of bicomponent         fibers,     -   the mixture comprises by weight between 30% and 70% of the first         family of materials, between 5% and 25% of the second family of         materials, between 10% and 30% of the third family of materials,         and between 5% and 25% of a mixture of bicomponent fibers,     -   the mixture comprises by weight between 20% and 60% of the first         family of materials, between 15% and 35% of the family of         materials, between 5% and 25% of the third family of materials,         and between 10% and 30% of a mixture of bicomponent fibers,     -   the method comprises, after the breakup step, a step for         detecting in the elements to be treated a plurality of         predetermined chemical compounds.

According to a second aspect, the invention deals with a non-woven material sheet obtained according to a method having the features above, the sheet including a mixture of bicomponent fibers and of at least one of the following material families: a first family of materials in majority containing polyurethane foam, a second family of materials in majority containing latex, a third family of materials containing textile fibers.

The sheet may further have one or several of the features below, considered individually or according to all technically possible combinations:

-   -   said mixture comprises by weight, between 60% and 90% of         polyurethane foam, between 2% and 15% of textile fibers, and         between 5% and 20% of the mixture of bicomponent fibers,     -   said mixture comprises by weight between 45% and 75% of         polyurethane foam, between 5% and 25% of latex, between 1% and         10% of textile fibers, and between 5% and 25% of the mixture of         bicomponent fibers,     -   said mixture comprises by weight, between 35% and 65% of         polyurethane foam, between 15% and 35% of latex, between 1% and         8% of textile fibers and between 10% and 30% of the mixture of         bicomponent fibers.

According to a third aspect, the invention deals with a facility for recycling furniture products, notably mattresses, bed bases and seats, which comprises:

-   -   a breakup device, in which base materials are obtained by         breaking up the furniture product;     -   a sorting device, in which the base materials are separated into         a plurality of families of materials, according to the nature of         the base materials;     -   a device for grinding the different families of the materials;     -   a mixing device, in which a mixer is prepared, the mixture         comprising a predetermined amount of at least one family of         ground materials;     -   a device for forming a non-woven unconsolidated sheet of         material from the mixture;     -   a device for consolidating the non-woven unconsolidated material         sheet;     -   a device for calendering the non-woven consolidated material         sheet.

Other features and advantages of the invention will become apparent from the detailed description which is given thereof below, as an indication and by no means as a limitation, with reference to the appended figures, wherein:

FIG. 1 is a diagram of steps, illustrating the method of the invention;

FIG. 2 is a simplified schematic illustration of the disinfection step by magnetic waves;

FIG. 3 is a simplified schematic illustration of the production lines for the steps for grinding, mixing, forming the unconsolidated sheet and for consolidation;

FIG. 4 is a simplified schematic illustration of the step for consolidating the unconsolidated material sheet.

The method which will be described below, and for which the main steps are schematically identified in FIG. 1, is intended to recycle bedding elements and seats at the end of their life. These bedding elements are, i.a., mattresses and bed bases. However, with the method it is possible to process other types of products: upholstered seats such as sofas, sofa beds, settees, convertible settees, armchairs, relaxation armchairs, scraps from the manufacturing of new mattresses and bed bases, this list not being limiting.

As illustrated in FIG. 1, the method includes the following steps:

-   -   a step 10 for receiving and unloading the elements to be         treated;     -   a step 14 for disinfecting the elements to be treated;     -   a breakup step 16 in which base materials are obtained by         breaking up the elements to be treated;     -   a sorting step 18, in which the base materials are separated         into a plurality of families of materials, according to the         nature of the base materials;     -   a control step 19, aiming at detecting in said elements a         plurality of predetermined chemical compounds;     -   a step 20 for grinding the different families of materials;     -   a mixing step 22, in which a mixture is prepared, the mixture         comprising a predetermined amount of at least one family of         ground materials, and more generally respective predetermined         amounts of several families of ground materials;     -   a step 24 for forming a non-woven unconsolidated material sheet         from the mixture;     -   a step 26 for consolidating the non-woven unconsolidated         material sheet;     -   a step 27 for calendering the non-woven consolidated material         sheet;     -   a step 28 for packaging the non-woven consolidated material         sheet and a step 30 for loading and dispatching the consolidated         material sheet.

These different steps will now each be detailed in turn.

In step 10, the elements to be treated are received and unloaded from the transport means.

The elements to be treated may include:

-   -   spring mattresses, which generally comprise an external textile         casing, and springs housed in the external casing;     -   mattresses with bags of springs; which comprise strings of         springs confined in textile bags, and a textile casing inside         which are placed the bags of springs;     -   foam mattresses, which comprise a textile casing and a foam core         housed inside the textile casing, the foam including a majority         of polyurethane; the foam generally includes more than 90% of         polyurethane and may include up to 100% of polyurethane;     -   latex mattresses, which include a textile casing and a latex         core housed inside the textile casing;     -   bed bases which generally include a rigid wooden or metal frame         and may include wooden slats, a textile casing, helicoidal metal         springs, etc.

The elements to be treated are elements at the end of their life, for example mattresses, bed bases, used seat cushions, and are then directly sent to the disinfection step 14. The elements to be treated which are not elements at the end of their life, for example scraps from the manufacturing of new mattresses and bed bases are directly sent to the grinding step 20, without passing through the disinfection step 14, or through the breakup 16 and sorting 18 steps.

The purpose of the disinfection step is to destroy bacteriological germs which may be present in the elements to be treated. Disinfection should be sufficient from a sanitary point of view in order to protect the operators working in the different steps of the method, and for guaranteeing perfect hygiene of the recycled finished products.

The disinfection step is not a sterilization step and is not aimed at entirely destroying the whole of the germs present in the elements to be treated.

The disinfection step aims at suppressing at least 99% of the bacteriological germs, preferably at least 99.9% of the bacteriological germs, still preferably at least 99.99% of the bacteriological germs.

The disinfection step is carried out either via a chemical route, or with electromagnetic waves.

The bed bases, the spring mattresses and the spring bag mattresses are treated via a chemical route. Foam mattresses and latex mattresses are treated either via a chemical route, or with electromagnetic waves.

Disinfection via a chemical route consists of spraying a disinfecting product on the external surface of the elements to be treated. This operation is performed in a hermetically sealed chamber. After spraying, the element to be treated remains in the chamber for a duration of about 2 hrs 30 mins.

The disinfecting product is for example the product with the trade name of ANIOS DVA HPH sold by the ANIOS laboratory. The amount of product used is of the order of a 8 ml for a mattress of a normal size.

Disinfection with electromagnetic waves is carried out by placing the element to be treated in a microwave tunnel, illustrated in FIG. 2.

The maximum power of the microwave generator used is 80 kW. Alternatively, the maximum power of the microwave generator is 60 kW.

The frequency of the magnetron which generates the microwaves is of about 2,450 MHz.

The element to be treated is subject to microwave radiation, which causes a rapid rise in temperature within this element. The power of the microwave radiation and the exposure time are selected according to the size of the mattress, to its thickness and to the material making up the core (polyurethane or latex foam). The power and the duration are selected so as to maintain the central layer of the mattress at a temperature of at least 70° C. for a period of at least 45 seconds. Preferably, the power and the duration are selected so as to maintain the central layer of the mattress at a temperature comprised between 70° C. and 90° C. for a duration comprised between 45 seconds and 90 seconds.

The exposure period is broken down into a heating period and a temperature-maintaining period. The heating period gives the possibility of bringing the central layer from room temperature up to a temperature above 70° C.

For a polyurethane foam mattress, the heating period is typically comprised between 30 seconds (a mattress of a size of 90×190 cm and with a thickness of 10 cm, power of 80 kW) and 180 seconds (mattress of a size of 180×200 cm and a thickness of 30 cm, a power of 60 kW).

For a latex mattress, the heating period is typically comprised between 30 seconds (mattress of the size of 90×190 cm and with a thickness of 10 cm, a power of 80 kW) and 230 seconds (a mattress of a size of 180×200 cm and with a thickness of 30 cm, a power of 60 kW).

In the breakup step 16, the disinfected elements are disassembled by the operators.

In the sorting step, the base materials obtained by breaking up of the elements to be treated are separated, preferably into five families of materials. The sorting is carried out depending on the nature of the base materials. The five families are the following:

-   -   a first family grouping the base materials which at the same         time meet both of the following conditions: the materials do not         contain any textile fibers, and they in majority contain         polyurethane;     -   a second family grouping the base materials in majority         containing latex;     -   a third family grouping the base materials containing textile         fibers;     -   a fourth family grouping the base materials in majority         containing wood;     -   a fifth family grouping the base materials in majority         containing metal.

In the first family, are essentially found the cores of the foam mattresses and the scraps from the manufacturing of the polyurethane foam mattresses.

In the second family, are found the cores of latex mattresses.

In the third family, textile coatings of mattresses and of bed bases are essentially found. These materials are generally multilayer materials, some layers being in textile and other layers for example being in polyurethane foam, in wadding, etc. Overall, these materials for example include between 15 and 25% of textile fibers, the remainder consisting of foam and of other substances.

In the fourth family, are found wooden structures of furniture seats, of bed bases or of other types of furniture, mainly storage furniture or interior decoration furniture.

The fifth family essentially includes the helicoidal springs which are found in spring mattresses, in mattresses with spring bags, and in bed bases, as well as the metal frames of bed bases or seats.

In step 19, the composition of certain materials of the elements to be treated is controlled. These materials are those which may contain chemical compounds which are not allowed in the finished product. These chemical compounds are for example VOCs (Volatile Organic Compounds), such as formaldehyde. The materials which may contain such chemical compounds are for example latex, polyurethane foams, adhesive residues, etc.

The inspection is carried out by taking a small amount of each material to be inspected, and by analyzing the composition of this sample in an automatic detection apparatus in order to check whether the sample contains a chemical compound appearing in a predetermined list. This apparatus may for example be a gas chromatography apparatus coupled with an F.I.D. (Flame Ionization Detector). If the material contains a chemical compound of the list, in an amount less than a predetermined threshold, this material is treated by the recycling method. The grinding and consolidation steps 20 and 26 actually allow removal of a significant fraction of the chemical compound, and ensuring that the concentration of said chemical compound in the non-woven consolidated product sheet is within the acceptable standards. The consolidation step applies a heat treatment, as explained later on, and is particularly efficient for removing the chemical compounds subject to regulations. The predetermined threshold is specific to each chemical compound. It depends i.a. on the removal rate of the chemical compounds in the grinding and consolidation steps, and on the composition of the non-woven material sheet (proportion of the material containing the chemical compound in the sheet).

If the material contains a greater amount of the chemical compound, than the predetermined threshold, then this material is not treated by the recycling method. It is for example sent to a controlled landfill, provided for accepting materials containing the detected chemical compound.

In the grinding step 20, the different families of materials are treated separately.

The first and second families of materials are processed with the same type of machine, but separately. The materials initially appear as blocks. The materials are ground into elements with a cubic shape, with a grain size comprised between 8 and 12 mm. The operation is carried out in two phases. In a first phase, the blocks are cut up into slices with blades, for example in a guillotine type machine. In a second phase, the slices are reduced into small size elements, for example in a granulator with a monorotor equipped with knives and a calibration hopper.

The third family of materials is for example processed in a roller grinder equipped with knives. The materials leave the grinders as lint fibers.

The fourth family of materials is ground into chips with a length comprised between 10 and 20 mm and a width comprised between 2 and 5 mm. The grinding operation is carried out in two phases. The materials are first processed in a rough grinder with a rotor, having grids with a separation of 40 mm. The materials from the rough grinder then pass into a secondary grinder, equipped with grids of about 4 mm. The chips are collected in bags.

Vibrating separators equipped with magnetic rollers are placed immediately downstream from each grinder. They allow separation of the metal parts from the other ground materials.

Alternatively, it is possible to directly grind the seats or the bed bases, without any preliminary breakup. In this case, for seats or bed bases having a wooden structure or frame, the sorting between the fourth family of materials (wood) and the fifth family of materials (metal) is carried out via magnetic rollers. The fourth family of materials then contains not only wood but also the textile trim of the box spring.

As regards the fifth family of materials, it is possible to provide that the helicoidal springs in good condition are separated and reused for making new mattresses, new bed bases or any other suitable product. The unusable springs and the other metal parts are ground in the same grinders as the fourth family of materials. They are then sent to a landfill or sold to scrap iron dealers.

At the end of the grinding step 20, the ground materials of the different families are transferred into dedicated storage units.

It should be noted that the grinding step causes partial removal of certain chemical compounds, for example VOCs. These compounds are for example released as a gas.

In step 22, a mixture is prepared from one or several families of ground materials. Predetermined amounts of the different families of ground materials are mixed with each other, these amounts being selected depending on the final product to be obtained.

Moreover, a mixture of bicomponent fibers is added to the mixture. This hot melt component after heating, is intended for consolidating the sheet of materials, as described later on.

Alternatively, other materials may be added to the mixture. For example an additional amount of textile fiber may be added to the mixture, depending on the finished product to be produced. It is possible to add to the mixture additives selected depending on the nature of the finished product. For example, the additives may include an anti-mite product, an anti-fire product . . . .

In a first exemplary embodiment, the finished product is a sheet of material of the non-woven type, with a thickness comprised between 5 and 20 mm. The weight of this sheet is typically comprised between 400 and 1,200 g/m², preferably between 600 and 1,000 g/m², and typically has the value of 800 g/m².

In order to produce such a sheet, a mixture is selected which comprises by weight:

-   -   between 40% and 80% of the first family of materials, preferably         between 50 and 70% of the first family of materials, and for         example 60% of the first family of materials;     -   between 15 and 45% of the third family of materials, preferably         between 25 and 35% of the third family of materials, and         typically 30% of the third family of materials;     -   between 5 and 20% of the mixture of bicomponent fibers,         preferably between 5 and 15% of the mixture of bicomponent         fibers, and typically 10% of the mixture of bicomponent fibers.

In a second exemplary embodiment, the finished product is a sheet of a material of the non-woven type, with a thickness comprised between 20 and 50 mm. The weight of said sheet is comprised between 1,200 and 2,200 g/m², preferably between 1,400 and 2,000 g/m², and for example has the value of 1,700 g/m².

In order to produce such a sheet, a mixture is selected which comprises by weight:

-   -   between 30% and 70% of the first family of materials, preferably         between 40 and 60% of the first family of materials, and         typically 50% of the first family of materials;     -   between 5% and 25% of the second family of materials, preferably         between 10 and 20% of the second family of materials, and         typically 15% of the second family of materials;     -   between 10% and 30% of the third family of materials, preferably         between 15% and 25% of the third family of materials, and         typically 20% of the third family of materials;     -   between 5% and 25% of the mixture of bicomponent fibers,         preferably 10 and 20% of the mixture of bicomponent fibers and         typically 15% of the mixture of bicomponent fibers.

In a third exemplary embodiment, the finished product is a sheet of a material of the non-woven type, with a thickness of more than 50 mm. The sheet for example has a density comprised between 2,000 and 4,000 g/m², preferably comprised between 2,500 and 3,500 g/m², and typically having the value of 3,000 g/m².

In order to produce this sheet, a mixture is selected which contains, by weight:

-   -   between 20% and 60% of the first family of materials, preferably         between 30% and 50%, for example 40% of the first family of         materials;     -   between 15% and 35% of the second family of materials,         preferably between 20% and 30%, for example 25% of the second         family of materials;     -   between 5% and 25% of the third family of materials, preferably         between 10% and 20%, for example 15% of the third family of         materials;     -   between 10% and 30% of the mixture of bicomponent fibers,         preferably between 15% and 25%, for example 20% of the mixture         of bicomponent fibers.

The bicomponent fibers consist of two components distributed over the whole length of the fiber. Each component may have different physical or chemical properties. The components may either be alternatives of a same type of polymer, or two types of totally different polymers. An example of such a fiber is marketed by MAX MODEL SA under the name of <<Polyester staple fiber, low melt 4/51 mm 110° C. flame retardant ref 4140>>. The use of other mixtures of bicomponent fibers may be contemplated.

In step 24, a unconsolidated material sheet is formed from the mixture, typically according to the method known under the name of <<airlay>> method. This method consists of forming a non-woven material sheet by dispersing the mixture in an air stream with high velocity, and by depositing the mixture transported by the air stream in a chamber. The air stream may be generated by overpressure, upstream from the chamber or by negative pressure downstream from the chamber.

Before passing to the step for forming the sheet 24, the mixture may pass into openers, which each include one or several rotary rollers provided with pins. These rollers have the main function of orienting the textile portions from the first family of materials, so as to unconsolidate the textiles and open the fibers. The rollers also allow kneading of the different materials of the mixture, and homogenization of this mixture.

At the output of step 24, the materials forming the sheet are not yet bound together and are positioned in bulk form on a belt.

In step 26, the non-woven material sheet is consolidated. This consolidation is carried out by a heat treatment. The unconsolidated material sheet is heated in an oven, for example to a temperature of the order of 180° C. The heat treatment causes partial melting of the mixture of bicomponent fibers, which contributes to binding together the different components of the mixture (textile fibers, latex, polyurethane, wood shavings).

This heat treatment also causes the removal of certain chemical compounds, for example VOCs and formaldehyde. These compounds may be thermally decomposed, or be released as a gas.

Concomitantly with the heat treatment operation, it is possible to laminate a coating layer on the sheet of material. It is possible to laminate any kind of layers: layers in fabric, layers in leather, decorative layers in plastic material, etc. Both faces of the sheet may thus be coated. Preferably, one of the faces is coated upstream from the heat treatment step and the other one immediately downstream from the heat treatment step.

After the heat treatment step 26, the sheet may pass to a calendering step and to a cutting step, in order to form parts with dimensions adapted to their final use. Alternatively, the sheet may not be cut out but wound and stored as a roll (packaging step 28).

Finally, the sheet is loaded and dispatched, either as a roll, or as parts having been already cut out (step 30).

The tunnel for microwave treatment is illustrated in FIG. 2. It comprises:

-   -   an enclosure 32, for example as a tunnel, provided with an entry         door 34 at a first end, and an exit door 36 at a second end         opposite to the first;     -   a microwave generator device 38, equipped with a plurality of         microwave generating elements 40 placed in the tunnel 32;     -   a main conveyor 42, positioned inside the tunnel 32 and provided         for moving the elements to be treated between both ends of the         tunnel 32, a conveyor 44 for bringing the elements to the         process, and a conveyor 46 for discharging the elements to be         treated after passing into the tunnel.

The microwave generating elements 40 are distributed above and below the conveyor 42. They are distributed over the whole length of the tunnel 32, from the first end as far as the second end of this tunnel. Each element 40 has a unit power comprised between 2 and 3 kW.

The main conveyor 42 may include a strip bearing protruding raised portions 52 on which the mattress lies. Thus, the mattress does not directly lie on the strip, and the major portion of the large face of the mattress turned towards the strip remains clear, i.e. without any contact with an element of the conveyor. This improves the microwave treatment.

The doors 34 and 36 are for example doors of the guillotine type.

Moreover, the tunnel includes a probe 54 for measuring surface temperatures of the element to be treated. The probe 54 operates by infrared pyrometry, and is suitable for measuring surface temperatures during the treatment with microwaves. The tunnel further includes a computer 56, provided for controlling the microwave generator device 38, the conveyors 42, 44 and 46, the doors 34 and 36, and the temperature probe 54.

The operation of the tunnel is the following:

The elements to be treated are brought one after the other by the supply conveyor 44 as far as the entry door 34. They are treated one by one inside the tunnel 32.

The computer 56 then controls the opening of the entry door 34. It then controls the starting of the conveyors 42 and 44 so as to have the element to be treated 57 penetrate inside the enclosure 32. The computer 56 then controls the closing of the entry door 34, and the starting of the microwave generator device 38. The power of the microwaves transmitted by the transmitters 40 and the exposure time of the element 57 to the microwaves are controlled by the computer 56 depending on the characteristics of the element to be treated. For mattresses, the computer notably takes into account: the material making up the core of the mattress (latex or polyurethane foam), the thickness of the mattress, the size of the mattress (length, width) and the bearing capacity of the mattress.

During the transmission of the microwaves, the element 57 is moved inside the tunnel by the main conveyor 42 according to reciprocal movements between both ends of the tunnel 32.

Once the treatment with microwaves is finished, the computer controls the opening of the exit door 36 and then the starting of the conveyors 42 and 46, so as to transfer the heated elements from the conveyor 42 as far as the conveyor 46.

The microwave tunnel may further include a station for automatically measuring the dimensions of the mattress (length, width, thicknesses), for example by means of cameras coupled with a unit for digital processing of the images. The measured dimensions are transmitted to the computer 56.

The computer 56 selects the program for treating the elements according to the measured dimensions and the noted bearing capacity.

The machines used for grinding the different families of materials are illustrated in FIG. 3.

As regards the first and second families, the blocks are first cut into slices by blades, for example in a machine 58 of the guillotine type. In a second phase, the slices are reduced into small size elements in a granulator 59 of the MG2000 MOLINARI type. The granulator is of the type with a monorotor equipped with knives and a calibration hopper.

The third family of materials is for example processed in a grinder 60 with rollers equipped with knives, of the SM500 McAfee Shredder type. As visible in FIG. 3, the facility may include two parallel lines dedicated to the third family of materials, each with a grinder 60. The materials leave the grinders as fiber lint.

The vibrating separators equipped with magnetic rollers, placed immediately upstream from each grinder, are not illustrated.

The materials of the first three families are stored in large volume containers 64, 65, 66. The grinders 60 are connected to the containers 64, 65, 66 through conduits. The materials are transferred along the conduits by pulsed air. The containers 64, 65, 66 may each be equipped with stirring means, for example air blowing nozzles which may be displaced inside the container. Wood shavings from the fourth family are stored in bags 63 and the metal parts of the fifth family in displaceable trays or containers 67. Each family of materials is thus stored separately from the other families of materials.

The mixing device 68 is schematically illustrated in FIG. 3. The device 68 comprises:

-   -   three metering devices 69, 70, 71, respectively dedicated to the         first, second and third families of materials;     -   a device 72 for dosing a mixture of bicomponent fibers;     -   a conveyor 73 fed by the dosage devices 69, 70, 71 and 72;     -   at least one opener 74, provided for kneading the materials         brought by the conveyor 73;     -   a device 75 for adding additives.

The dosage devices 69, 70, 71 are silos, each having an internal volume provided for receiving an amount from the first family, from the second and from the third family of materials respectively. Each silo 69, 70, 71 is equipped with sensors adapted for measuring the weight of materials loaded inside the internal volume. The silos 69, 70, 71 are connected through transport conduits to the storages 64, 65, 66 dedicated to the first, second and third families of materials respectively. The transfer is carried out via a pulsed air device.

Each silo 69, 70, 71 is equipped in the lower portion with an outlet located vertically above the conveyor 73. Each of the silos is equipped with a control valve, with which the outlet may be selectively opened and closed.

The mixture of bicomponent fibers appears as a block of fibrous material. The device 72, dedicated to the dosage of the mixture of bicomponent fibers, includes a tool provided for nibbling the block of the mixture of bicomponent fibers and for producing shavings, a cell for weighing the shavings and a unit for transfer from the weight cell towards the conveyor 73.

The nibbling tool may be of any suitable type, and for example includes a plurality of spikes in order to detach the bicomponent fibers of the compressed block.

The fibers detached by the nibbling tool are transferred to the weighing cell for example by a conveyor belt. They are transported from the weighing cell to the conveyor 73 through a chute or by another conveyor belt.

In the exemplary embodiment illustrated in FIG. 3, the device 68 includes three openers 74 placed in series. The material deposited on the conveyor 73 at the end of said conveyor, are discharged into the first opener 74.

The three openers 74 are of the same type.

The device 75 is for example inserted between the first and the second opener 74. It is provided for adding to the mixture additives selected according to the nature of the finished product. For example, the additives may include an anti-mite product, an anti-fire product . . . .

The openers 74 and the device 75 are connected together through connecting conduits. The mixture is transferred along the conduits by pulsed air.

The device for forming the unconsolidated material sheet, and the heat treatment device are schematically illustrated in FIG. 3. The device 80 for forming the sheet is of the type described in Italian patent application No. P02007/A000021. This device includes two negative pressure chambers, and is particularly well adapted to the treatment of a mixture containing a strong proportion of polyurethane and of latex.

The last opener 74 is connected to the device for forming the sheet 80 through a conduit. The mixture is transferred along the conduit for example by pulsed air.

The sheet 82 leaving the device 80 is transported on a conveyor and penetrates into an oven 84 so as to undergo the heat treatment therein. The oven for example has a total length of 5 m, and is divided into two chambers placed in series with each other. It is heated by gas burners 85. It is equipped with fans for allowing circulation of the air heated by the burners inside both chambers. The device is equipped with two conveyors placed inside the oven 84, as visible in FIG. 4. The lower conveyor 86 is placed in the extension of the conveyor 88, which ensures transport of the sheet from the device for forming the sheet 80 as far as the oven 84. The conveyor 86 ensures transport of the sheet through the oven 84 from the entry 90 as far as the exit 92. The upper conveyor 94 is placed above the conveyor 86. The vertical separation of the conveyor 94 relatively to the conveyor 86 is adjustable, so that the conveyor 94 calibrates the thickness of the sheet 82 at the entry of the oven. The conveyor 94 substantially extends over the whole length of the oven, from the entry 90 to the exit 92.

The sheet 82 undergoes cooling at the exit of the oven 84, first by projection of cold air via nozzles 96, and then calendering by means of cooled rollers 98. Downstream from the calendering rollers 98, a device 100 may be placed (FIG. 3) capable of steering the sheet 82 either towards a cutting unit 102 or towards a storage roll 104.

As visible in FIG. 4, the heat treatment device may further include an assembly 106 allowing lamination of a coating layer 108 on one of the faces of the sheet 92, here the upper face. The assembly 106 is placed immediately upstream from the oven 84. A similar device 110 is placed downstream from the calendering rollers 98, so as to laminate another coating layer 112 on the opposite face of the sheet 82, here the lower face.

The device also allows cold calendering of the sheet, a mechanical operation intended to stabilize and set the desired sheet thickness, which is obtained according to the calendering degree (pressure and cooling temperature) through which the sheet undergoes a thermal shock. It may be used as a throughput regulator and as a degasser for air and/or the volatile materials present from the upstream portion of the process.

As visible in FIG. 3, the material scraps from the device for forming the sheet 80 are collected and sent back via the line 114 as far as the conveyor 73. After grinding in a grinder 116, these materials are recycled on this conveyor 73.

The mixing device 63 further includes a suction unit 118, provided for sucking up the wood shavings and for transferring them towards one of the silos 69, 70 or 71.

The wood shavings at the outlet of the grinders 61 and 62 are collected in containers, for example in bags 63. These bags 63 are then transported in proximity to the conveyor 73, the wood shavings may consequently be sucked up by the device 118.

The recycling facility is further equipped with a centralized ventilation device 105, provided with air extractors suitable for sucking up the air in the main pieces of equipment of the facility: the grinders for the third family of materials, the granulator for the first and second families of materials, the silos, the openers, the device 80 for forming the sheet. The dusts are trapped on a filter, for example a sleeve filter. They may for example be reused for roadway surfacing.

The sheets obtained by the method above may find multiple applications. The sheets containing a strong proportion of polyurethane may be used as components of finished products for furniture, notably for protecting box spring slats, as a mattress booster, as filling in the trays of mattresses. These sheets may also be used as a heat and sound insulator for the building sector, or as padding for automobiles.

The sheets described above may also be made from materials which do not stem from the recycling of bedding elements or of furniture or of manufacturing scraps. The materials may be raw materials directly supplied from the suppliers, especially for the production of the sheets.

In the first exemplary embodiment, the finished product is a sheet of a non-woven type material, with a thickness comprised between 5 and 20 mm. The specific gravity is typical, comprised between 20 and 60 kg/m³, preferably between 30 and 50 kg/m³, and for example has the value of 40 kg/m³.

The mixture comprises in this case, by weight:

between 50% and 90% of polyurethane foam, preferably between 70% and 85% of polyurethane foam, and typically between 80% and 85% of polyurethane foam

between 2% and 15% of textile fibers, preferably between 3% and 10% of textile fibers, and for example between 4% and 8% of textile fibers

between 5% and 20% of the mixture of bicomponent fibers, preferably between 5% and 15% of the mixture of bicomponent fibers, for example between 8 and 12% of the mixture of bicomponent fibers.

The finished product, i.e. the consolidated sheet, without the optional laminated coatings, substantially has the same mass composition.

For example, the consolidated sheet comprises by weight, 84% of polyurethane foam, 6% of textile fibers and 10% of mixture of bicomponent fibers.

In the second exemplary embodiment, the finished product is a sheet of a material of the non-woven type, with a thickness comprised between 20 and 50 mm. The specific gravity of the sheet is comprised between 25 and 65 kg/m³, preferably between 55 and 65 kg/m³, and typically has the value of 46 kg/m³.

Static fatigue tests were carried out for this sheet, according to the NFT56116 standard. The height loss was about 1.4 mm. Moreover dynamic fatigue tests were carried out for said sheet, according to the NF EN IS03385 standard. The height loss was of about 13.5 mm, with a hardness loss of 14.6%.

The mixture comprises for this exemplary embodiment, by weight:

between 45% and 75% of polyurethane foam, preferably between 55% and 75% of polyurethane foam, for example between 65% and 70% of polyurethane foam;

between 5% and 25% of latex, preferably between 10% and 20% of latex, for example between 13% and 17% of latex,

between 1% and 10% of textile fibers, preferably between 2% and 7% of textile fibers, for example between 3% and 5% of textile fibers,

between 5% and 25% of the mixture of bicomponent fibers, preferably between 10% and 20% of the mixture of bicomponent fibers, for example between 13% and 17% of the mixture of bicomponent fibers.

In the third exemplary embodiment, the finished product is a sheet of a material of the non-woven type, with a thickness of more than 50 mm.

The specific gravity of the sheet is comprised between 40 and 80 kg/m³, preferably between 50 and 70 kg/m³, and typically has the value of 60 kg/m³.

Statistical fatigue tests were carried out on this sheet, according to the NFT56116 sheet. The height loss was of about 0.5 mm.

Dynamic fatigue tests were also carried out for this sheet, according to the NF ENISO 3385 standard. The height loss was of about 8.8 mm.

The hardness loss is of the order of 14.6%.

The mixture comprises for this exemplary embodiment, by weight:

between 35% and 65% of polyurethane foam, preferably between 45% and 60% of polyurethane foam, for example between 50% and 55% of polyurethane foam;

between 15% and 35% of latex, preferably between 20% and 30% of latex, for example between 22% and 27% of latex;

between 1% and 8% of textile fibers, preferably between 2% and 6% of textile fibers, for example between 2% and 4% of textile fibers;

between 10% and 30% of the mixture of bicomponent fibers, preferably between 15% and 25% of the mixture of bicomponent fibers, for example between 17% and 22% of the mixture of bicomponent fibers. 

1. A method for recycling furniture products, notably mattresses, bed bases (46) and seats, the method comprising the following steps: a breakup step, in which base materials are obtained by breaking up the bedding product; a sorting step (18), in which the base materials are separated into a plurality of families of materials, according to the nature of the base materials; a step (20) for grinding the different families of materials; a mixing step (22), in which a mixture is prepared, the mixture comprising a predetermined amount of at least one family of ground material; a step (24) for forming a sheet of non-woven unconsolidated material from the mixture; a step (27) for consolidating the non-woven unconsolidated material sheet; a step for calendering the non-woven consolidated material sheet.
 2. The method according to claim 1, characterized in that, in the sorting step (18), the base materials are sorted so as to separate at least first and third families of materials, the first family of materials grouping the base materials which both do not contain textile fibers but in majority contain polyurethane, and the third family of materials grouping the base materials containing textile fibers.
 3. The method according to claim 1, characterized in that, in the sorting step (18), the base materials are sorted so as to separate at least one second family of materials, grouping the base materials in majority containing latex.
 4. The method according to claim 1, characterized in that it comprises a step (14) for disinfecting the elements to be treated, before the breakup step (18).
 5. The method according to claim 4, characterized in that the disinfection of the elements to be treated is carried out via a chemical route by spraying a disinfectant on an external surface of the bedding elements, or by exposing the bedding elements to microwave radiation.
 6. The method according to claim 1, characterized in that, in the step (24) for forming the non-woven unconsolidated material sheet, the mixture is carried away and dispersed by an air flow and deposited in a chamber, according to the method known as the air lay method.
 7. The method according to claim 1, characterized in that, in the consolidation step (26), the non-woven unconsolidated material sheet is thermally consolidated.
 8. The method according to claim 2, characterized in that the mixture comprises by weight, between 40% and 80% of the first family of materials, between 15% and 45% of the third family of material, and between 5% and 20% of a mixture of bicomponent fibers.
 9. The method according to claim 3, characterized in that the mixture comprises by weight, between 30% and 70% of the first family of materials, between 5% and 25% of the second family of materials, between 10% and 30% of the third family of materials and between 5% and 25% of a mixture of bicomponent fibers.
 10. The method according to claim 3, characterized in that the mixture comprises by weight between 20% and 60% of the first family of materials, between 15% and 35% of the second family of materials, between 5% and 25% of the third family of materials, and between 10% and 30% of a mixture of bicomponent fibers.
 11. The method according to claim 1, characterized in that it comprises, before the breakup step, a step for detecting in the element to be treated a plurality of predetermined chemical compounds.
 12. A non-woven material sheet obtained by the method according to claim 1, the sheet including a mixture of a bicomponent fiber mixture and of at least one of the following families of materials: a first family of materials in majority containing polyurethane foam, a second family of materials in majority containing latex; a third family of materials containing textile fibers.
 13. The sheet according to claim 12, characterized in that said mixture comprises by weight, between 60% and 90% of polyurethane foam, between 2% and 15% of textile fibers, and between 5% and 20% of the mixture of bicomponent fibers.
 14. The sheet according to claim 12, characterized in that said mixture comprises by weight, between 45% and 75% of polyurethane foam, between 5% and 25% of latex, between 1% and 10% of textile fibers, and between 5% and 25% of the mixture of bicomponent fibers.
 15. The sheet according to claim 9, characterized in that said mixture comprises by weight, between 35% and 65% of polyurethane foam, between 15% and 35% of latex, between 1% and 8% of textile fibers, and between 10% and 30% of the mixture of bicomponent fibers.
 16. A facility for recycling bedding elements, mattresses, bed bases and seats, the facility comprising: a breakup device, in which the base materials are obtained by breaking up the furniture product; a sorting device, in which the base materials are separated into several families of materials, depending on the nature of the base materials; a device (58, 59, 60) for grinding the different families of materials; a mixing device (68), in which a mixture is prepared, the mixture comprising a predetermined amount of at least one family of ground materials; a device (80) for forming a non-woven unconsolidated material sheet from the mixture; a device (84) for consolidating the non-woven unconsolidated material sheet; a device (98) for calendering the non-woven consolidated material sheet. 